iDEFENSE Intelligence Operations discovered security issues in improper
file and directory permissions during an audit of
<http://www.astaro.com/> Astaro AG's Astaro Linux. Astaro Linux designates
a number of files and directories as world writeable that should probably
not be. This, combined with other more serious flaws, could potentially
result in system compromise or denial of service.

DETAILS

Analysis:
World writeable files and directories are dangerous because any user on
the system, even one running in a restricted account such as "nobody" can
access the files, write to them, and potentially delete them. World
writeable directories can be especially dangerous when they are used to
store files covertly. Any directories and files contained within the world
writeable directory can potentially be modified.

Several sensitive configuration files and directories are world writeable,
meaning an attacker with any level of access to the root file system could
cause damage or subvert the services/applications relying on those files.

The following files are world writeable:
/etc/protocols
/etc/ssh/ssh_host_dsa_key.pub
/etc/ssh/ssh_host_key.pub

It is unknown whether the following files need to be world writeable for
the system to function properly, but it appears safe to remove the world
writeable attribute:

These commands will list all world writeable directories and files
respectively. Some of the directories, such as /tmp, are meant to be world
writeable, and leaving them as such is relatively safe.

Workaround:
Removing the world writeable bit on the files can be accomplished using
chmod:
chmod o-w filename

This will work for both files and directories.

Vendor response:
<mailto:mhennig@astaro.com> Markus Hennig of Astaro promptly confirmed
the incorrect file permissions and worked with us responsibly to resolve
these issues. The latest Up2Date 2.022 fixes the file permissions, which
is now currently available on Astaro Up2Date servers.

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